The invention relates to the treatment of fibers of tobacco or other smokable materials, and more particularly to improvements in methods of and in apparatus for treating accumulations of such fibers. Still more particularly, the invention relates to improvements in methods of and in apparatus for regulating the mass flow of fibers in streams of fibers of tobacco or other smokable materials.
As used herein, the term "fibers" is intended to denote fibers of natural tobacco, reconstituted tobacco, artificial tobacco and filter material for tobacco smoke.
A machine for making a tobacco rod or a filter rod normally comprises a conveyor which defines for the fibrous material an elongated path and receives fibrous material from a duct or another suitable supplying device in such quantities that it builds up a stream with a surplus of fibrous material. The stream is attracted to the conveyor by suction, and the surplus is removed by a suitable trimming or equalizing device so that the trimmed stream constitutes a filler which is ready to be draped into a web of cigarette paper or other suitable wrapping material, the draped filler and the wrapping material together forming a continuous rod which is thereupon subdivided into rod-shaped smokers' products or filter rod sections of unit length or multiple unit length.
The density of the stream on the conveyor can be monitored upstream of the trimming station and the position of the trimming device relative to the conveyor is adjusted if the monitored density deviates from a desired or optimum density. Such regulation is intended to eliminate or to counteract short-range deviations of the characteristics of the untrimmed stream from a optimum value.